Offshore ice slurry production coupled with deep-sea cold energy for on-site wind power utilization: Techno-economic evaluation

On-site utilization of offshore wind power can mitigate challenges posed by long-distance transmission and grid integration. Meanwhile, using offshore wind power for cold energy storage provides an efficient approach to meeting the demand for offshore refrigeration. This paper investigates an offshore ice slurry production system and presents a comprehensive 3E evaluation (i.e., energy, exergy, and economic evaluation) of four typical configurations. The results indicate that using deep-sea cold water as both the condenser coolant and a raw material for ice slurry production enhances overall system thermodynamic performance. Within the thermocline zone, the rapid decrease in seawater temperature enables direct seawater-cooled configurations to achieve a total coefficient of performance of 5.08 and specific energy consumption of 29.76 kWh/ton, significantly outperforming air-cooled configurations. Then, economic analysis reveals that the thermodynamic performance enhancement gained from deep-sea cold energy outweighs the costs of seawater pipelines and installation. At the optimal compromise point in multi-objective optimization, the direct seawater-cooled system achieves a system exergy efficiency of 39.37% and a levelized cost of storage of 0.1405 $/kWh. Finally, a sensitivity analysis demonstrates that the direct seawater-cooled configuration maintains robust stability even as key economic and operational parameters fluctuate. This research demonstrates that the offshore ice slurry production system, coupled with deep-sea cold energy, offers favorable technical and economic characteristics, effectively meeting offshore cold energy demands while enabling on-site wind power utilization.